1. Field of the Invention
The present invention relates to a container for containing a liquid, the container being made of a flexible plastic lamination sheet.
2. Description of the Related Art
In recent years, there has been a movement to reduce consumption of natural resources. Also, it has become increasingly difficult to properly dispose of ever increasing amounts of garbage and refuse. Taking these circumstances into consideration, liquid containers formed from a thin plastic film have become increasingly popular. Liquid containers contain liquid such as liquid detergent, and are used to refill thick plastic bottles with the liquid. By using liquid containers, then the empty thick plastic bottles need not to be disposed of so that natural resources are preserved and amounts of refuse are reduced.
As shown in FIG. 15, a conventional liquid container 101 is a flat pouch formed by overlapping two substantially rectangular sheets of flexible plastic film and fusing together opposing edge portions of the film sheets. Liquid detergent L or some other liquid is sealed in the liquid container 101 via an upper seal fused portion 109a, which forms the spout of the pouch, a lower fused portion 109b, which forms a bottom portion 103 of the pouch, and side fused portions 109c. The sealed region of the upper fused portion 109a is thinner at its central portion so that when an empty plastic bottle is to be refilled with liquid L, the upper fused portion 109a is cut along the broken line 110 shown in FIG. 15 to open up a spout 102 near the central portion of the upper fused portion 109a. Liquid L can then be poured through the spout 102 into the empty plastic bottle (not shown in the drawings) in order to refill the empty plastic bottle.
When the conventional liquid container 101 is filled with liquid L, the two plastic film sheets forming the liquid container 101 separate from each other to form a container shape for holding the liquid, However, the container shape of the liquid container 101 is unstable to that the liquid container 101 must be held with both hands in order to accurately pour all of the liquid into the plastic bottle without spilling. Also, the spout 102 is substantially two dimensional. Because of this and because the two sheets of plastic film tend to move toward each other, it is very likely that the spout 102 will not open up sufficiently and that the sheets of plastic film will cling to each other at the spout 102. When the spout 102 does not sufficiently open up, liquid can creep between the sheets of plastic film toward the spout 102 by force of capillary action. As a result, liquid can flow out from unexpected and undesired positions of the spout 102. Further, because the liquid clings to and is supported between the two sheets of film, the liquid in the liquid container 101 can not be totally poured out to the last drop when refilling the plastic bottle.
It is difficult to fill the flat pouch shaped container with liquid at the factory, for example, unless gas has been completely removed from the container. This is especially the case when the container is to be filled with a liquid detergent. When the gas is incompletely removed from the container, air can mix with the liquid detergent while the liquid detergent is being introduced into the container. The air mixing with the liquid detergent can froth up into bubbles that take up space in the container. As a result, it is difficult to fill the container with a desired amount of liquid detergent.
In another aspect, a bottle or a container formed of a lamination sheet is conventionally used for containing therein a sticky food such as a mayonnaise. Such bottle has an upper portion provided with a cap and is deformable for squeezing the content out of the bottle. The lamination bottle is formed by blow molding technique and has three layers including polyethylene (PE), a copolymer of ethylene and vinyl alcohol (EVOH), and polyethylene (PE). The cap and the EVOH layer can provide oxygen blocking function so as to obviate oxidation of the content.
However, in case of the lamination bottle, air may be entered into the bottle by an amount corresponding to a consumption amount of the content. In order to eject air in the bottle, the bottle must be pressedly deformed against the restoration force of the bottle, while attention is drawn to the accidental discharge of the content through the pouring portion during the air discharge work, and then the cap must be placed on the pouring portion and then is fastened. Further, since the bottle is formed by the blow molding, a relatively large thickness of the EVOH layer is required in order to distribute the EVOH material over an entire area of the bottle. This causes increase in production cost, and further, the produced bottle is bulky. Accordingly, the lamination bottle is costly and requires relatively increased labor in production, transportation, and retention of the content within the bottle.